Diversity can often lead to misunderstanding and diminishing commercial returns, as many a straitjacketed pop star has found out to their misfortune. The general rule of thumb in pop music - from as far back as the 1950s to right here, right now - appears to be stylistic rigidity in output, an aesthetic similarity that borders on insult for the concerned, involved listener and creative stagnation for the, ahem, artiste.
In the case of Joe Jackson, singer, pianist, band leader, composer and now author (his autobiography A Cure For Gravity has just been published), his very eclecticism has generated accusations of selling out his working-class roots. That he has become a pop star who has not just snubbed pop music but who has diversified far beyond it is galling for those who think the use of three chords and corny lyrics contains the missing link between entertainment and enlightenment.
"As a lad in Portsmouth, I felt a bit of a misfit," he says from a hotel in London, where he is currently engaged in promotional duties for his autobiography and his latest album, the rather self-explanatory Symphony No 1. "Working-class lads from Pompey don't write symphonies, do they? I'm very guided by intuition, and I write what seems to want to get written. To me, writing classical music is a natural progression. When I do something that shows a different side of me, people are perhaps more likely to think that I've gone off in a different direction. They tend to see just one side of me, which is the hit singles."
It is a sad but certain fact of life that people who claim to be interested in pop and/or rock music prefer the easy way out. At the supermarket, people get used to the toilet rolls being in the same place week after week. Their mental comfort zone becomes frustrated and confused when the same goods are changed around for no outwardly logical reason. In music terms, this is why someone such as Shania Twain - the pop equivalent of Extra Soft Luxury Toilet Rolls For Ultra Sensitive Bottoms - sells more music than, say, Blur, Beck or REM.
"It's just the way it works," reasons Jackson amiably, his apparent lack of bitterness resolved over the years by a keen understanding of pop's fickle marketplace. "The fact is that most people are not going to put a lot of effort into following the career of a rather eclectic artist who is not in the pop charts. I still have enough of an audience, however, to sell out seven shows in New York, or wherever, to keep making records and to keep paying the rent. That's all I ever really wanted in the first place, and indeed all I ever hoped for. I prefer it this way, to be honest. The height of my pop success [1979 to 1984] was where a lot of people came along to the gigs because I happened to be the right flavour. Now they come along because they want to be there, they're genuinely interested. It feels more real that way."
Born in Burton-on-Trent in 1955, Jackson moved to Portsmouth as a child. In his teens, he gained entrance to London's Royal College of Music, where he studied piano, percussion, composition and orchestration. To help out with his expenses throughout his three-year stint in London, Jackson worked nights and weekends in a series of karaoke pop bands and played piano at Portsmouth's Playboy Club. Come punk rock's summer of hate in 1976, Jackson had been turned off by classical music and embraced rock with a vengeance; he was signed by A&M in 1978, and his debut album, Look Sharp, was released a year later. In the thick of sniffling post-punk and the artier side of New Wave, his confident, thoughtful and ironic lyrics brought him into the limelight.
"The early stages of it was great, because I was doing things for the first time," he recalls. "Going on Top Of The Pops and touring all over Europe was fantastic. After a while, though, it became unreal, a bit of a grind. Then I just hit the wall - one tour too many, one album too many. I took some time off to have a re-think."
Jackson says he's "at a different place now" and reckons the best times he has experienced in his career were during those halcyon days - and right now. "I feel free and do what excites me. I feel much closer in some ways to how I felt about music as a teenager. I have more in common with my 15-year-old self than I did with my 35-year-old self. I suppose I got my priorities straight.
"Pop success is inevitably followed by pop failure, if you like. It seems like that, anyway, because if one record sells a million records and your next sells half a million, you're being set up to feeling as if you've failed - when, in fact, selling half a million is pretty damned good. So you have to deal with that and learn not to take it personally."
A Cure For Gravity was written, says Jackson, "to put some things in perspective, to tell the story of struggle and failure and trying to become a musician." He also wanted to say some things about music (which he does at length, his hectoring, lecturing tone the only flaw in an otherwise engaging, unfailingly honest book). Another reason was to entertain people and to clear up misconceptions about him that he feels have been doing the rounds for years.
"The thing that most annoys me is that, because what I do musically is more diverse than just writing three-minute pop songs, people tend to typecast me as being snobby and arrogant and pretentious," he says, at pains to distance himself from the image of an archetypal whining pop star. "This drives me nuts, because those are facets of the personality that I detest. I tend to get typecast as that New Wave guy who had a couple of hits but who then went off and thought he was too good for pop music."
It's instructive to note that of all the Class of 1979, a mere handful have diversified into areas beyond the fundamental remit of pop and rock. When he first started Joe Jackson was, more often than not, compared to Elvis Costello, a contrast that Jackson, perhaps justifiably, frowned upon. Twenty years down the line, he says there are obvious comparisons that nevertheless remain valid.
"We put aside somewhat more sophisticated ideas that we might have been interested in exploring, and as time has gone by we haven't so much changed as revealed more sides of ourselves. We're both throwbacks to a pre-rock'n'roll era, where you could be a more complete musician. I'm not making comparisons because that's a dangerous area to get into, but the kind of people I respect and would like to identify with would be the likes of Gershwin, Duke Ellington, Leonard Bernstein - people who wrote symphonies, Broadway musicals, pop songs, piano concertos and opera. And why shouldn't they?
"There was a cultural shift in the 1950s and 1960s away from learning your craft and earning your dues to just learning three chords and having the attitude that anyone can do it. On the one hand that is very liberating and exciting, but on the other it's very limited - the result of which is, I get accused of being a snob. Which is funny, because I like rock'n'roll as much as the next guy."
In his book, Jackson writes that music saved his life. I take this to mean his creative, social and aesthetic existence - except he meant it quite literally. "To a certain extent I mean it literally, in that I don't know what I would have done without music," he says, with a certain level of passion in his voice. "It has given me something into which I can pour my craziness, my angst and depression. Without it I might have ended up sleeping on the street in a cardboard box. Or become an alcoholic, or God knows what. I couldn't bear to grind away at a boring nine to five job, and I'm not being judgmental there.
"Even if I'd never had a hit record, I might have ended up playing pubs somewhere. I'd still rather do that than anything else."
A Cure For Gravity by Joe Jack- son is published as a paperback original by Anchor, £9.99 in UK. Symphony No 1 is on Sony Classical.
